Is Robert Rackstraw hijacker D.B. Cooper? Former Army paratrooper trained in Alabama

A decoded message from 1972 has solved the mystery of infamous hijacker D.B. Cooper, a documentary filmmaker claims.

Television and film producer Tom Colbert said the letter, sent to The Oregonian and obtained by suing the FBI for the Cooper files, points to a Vietnam veteran named Robert Rackstraw as the leading suspect. Rackstraw's name has been mentioned frequently by those investigating the unsolved 1971 hijacking, including in Colbert's 2016 book "The Last Master Outlaw," and the History Channel documentary "D.B. Cooper: Case Closed."

On Nov. 24, 1971, a man identified as "D.B. Cooper" hijacked a Boeing 727 as it flew between Portland and Seattle. He demanded and received $200,000 in ransom money before parachuting out of the plane over the Northwest. He was never seen again but letters from someone taking credit for the hijacking appeared at newspapers through the years.

As part of his investigation, Colbert contacted Rick Sherwood, a former member of the Army Security Agency who served with Rackstraw, to decode the recently obtained letter. Sherwood claims it contains a confession that includes Rackstraw's initials, the Army's Special Warfare School he attended and one of his military units.

Rackstraw is a former paratrooper and Vietnam veteran. In 1969, he was stationed at Fort Rucker, Alabama for chopper and fixed-wing flight training before deploying to Vietnam. Records show he returned to Fort Rucker in 1971, where he was detained for domestic assault. A later military investigation showed Rackstraw was accused of falsifying his college records and lying about his rank and medals and was forced to resign from the Army.

Colbert believes Cooper was working for the CIA, which covered up his identity in connection to the hijacking. Rackstraw was cleared by the FBI in 1979; the bureau officially closed the Cooper case without resolution in 2016.

The case remains the only unsolved case of piracy in the history of U.S. aviation.